The International Court of Justice (ICJ) gave its ruling in a border row between Benin and Niger on Tuesday, awarding the majority of 25 disputed islands in the Niger River, to Niger, including the largest one, which was at the heart of the dispute.
Niger was awarded 16 of the disputed islands along a 150 km stretch of the river where it forms the border between the two countries, including 60 square km Lete, the largest island, which had been the cause of sporadic border clashes.
The government in Niamey already receives taxes from the handful of people who live on Lete island. Most of them are livestock herders.
Benin and Niger, which are two of the world's poorest countries, have both claimed ownership of the 25 islands since they won independence from France in 1960.
The West African nations headed to the UN court in The Hague in 2002, promising to abide by its decision.
The panel of five judges which examined the case said in a four-to-one majority ruling that it had allocated 16 of the disputed islands to Niger, with the other nine falling to Benin.
It also delineated the boundaries between the two countries in the River Niger and the River Mekrou.
Tuesday's ruling is final and cannot be appealed.
Lete is situated close to the main border crossing between the two countries at Malanville, where the main highway from the port of Cotonou to the Niger capital Niamey crosses the River Niger on a bridge.
A series of clashes over Lete island the early 1960s left eight Niger nationals dead and the dispute has smouldered on since then.
It flared up again in 2000 when Benin began erecting a government administration building on the island. Niger sent soldiers to stop the construction work and Benin responded by temporarily blocking food shipments to its landlocked neighbour.
Both governments have both vowed to abide by the ICJ's decision.
In a broadcast to the nation on Monday night, Niger's Prime Minister Hama Amadou called on the population of his country to accept the court's verdict, whichever way the decision went.
"Defining a clear border between our two countries can only reinforce peace and good neighbourly relations," he said.
Reuters news agency quoted Benin's Foreign Minister Rogatien Biaou as saying after the ICJ verdict that his country still believed the border should have been on the far bank of the rivers, granting Benin possession of all the islands, but it would accept the ruling.